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bashawksedheader
Dalek
Dalek

Reputation: 4318

Adding header to an ascii catalogue

I would like to add a header to an ascii file using bash script. What is the shortest way to do it without making temporary text file?

Upvotes: 0

Views: 275

Answers (2)

Tom Fenech
Tom Fenech

Reputation: 74685

You can use the BEGIN block in awk to print some output before the file is processed:

awk 'BEGIN{print "header text"}1' input.txt > output.txt

A newline will be appended after the header string. If this is undesired, you can use printf instead. The 1 at the end is a shorthand, which means that all the lines in the file are printed.

In order to overwrite the original file, you can just use a temporary file:

awk 'BEGIN{print "header text"}1' input.txt > tmp && mv tmp input.txt

Upvotes: 1

Kalanidhi
Kalanidhi

Reputation: 5092

You can try this way

sed '1 i\Header' FileName

Example:

seq 5 | sed '1 i\\tHeader'

Output:

    Header
1
2
3
4
5

Upvotes: 4

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